🐛 Fix override for C platforms

After calling `overrideFactory` on a C platform, the `override` function
was dropped from the resulting set.

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## Fixed
+- Overriding the factory of a C platform caused the 'override' function
+  to disappear from the resulting set.
+
 ## [4.1.4] - 2024-06-03
 
 ## Fixed

c/default.nix

@@ -32,34 +32,35 @@ let
               sha256 = "sha256:10m80cpdhk1jqvqvkzy8qls7nmsra77fx7rrq4snk0s46z1msafl";
             } else mathjax;
 
-      inner =
+      mkPlatform =
         { name
         , pkgs
         , stdenv ? pkgs.stdenv
         , output ? null
         , platformOverrides ? _: { }
-        }:
+        , factoryOverrides ? { }
+        }@args:
         let
-          factory = pkgs.callPackage (import ./make-derivation.nix platformOverrides)
-            {
+          factory = pkgs.callPackage
+            (import ./make-derivation.nix platformOverrides)
+            ({
               inherit base stdenv components;
               targetName = name;
               mathjax = mathjax';
-            };
+            } // factoryOverrides);
 
           finalPlatform = factory:
             {
               inherit name pkgs;
               __functor = _self: factory;
+              override = overrides:
+                mkPlatform (args // overrides);
               overrideFactory = overrides:
-                finalPlatform (
-                  factory.override overrides);
-            } // lib.optionalAttrs (output != null) { inherit output; };
+                finalPlatform (factory.override overrides);
+            } // { inherit output; };
         in
         finalPlatform factory;
 
-      mkPlatform = lib.makeOverridable inner;
-
       platforms' = {
         _default = mkPlatform {
           inherit pkgs;